Disease Control

Anthracnose Leaf Curl (Colletotrichum fioriniae and C. nymphaeae)

Celery anthracnose is caused by the fungi Colletotrichum fioriniae and C. nymphaeae (formerly C. acutatum). C. fioriniae also causes bitter rot in apples while C. nymphaeae causes anthracnose of strawberries and garlic scapes. Symptoms on celery include curled leaves, occasional discoloration of leaf margins, twisted petioles, and lesions on petioles. Leaves remain green but often appear fan-like and curl downward. Leaf curl is often the most prominent symptom observed and can resemble injury from growth regulator-type herbicides (e.g., 2, 4-D). In advanced stages, the disease can resemble blackheart, the physiological disorder caused by low calcium assimilation. These pathogens thrive under warm, wet conditions. Rapid pathogen growth occurs when temperatures are 77°F–86°F, with substantially more disease development at 86ºF. Temperatures as cool as 60°F will support fungal growth and spread, but field progression will be slow. This disease may be seedborne. Start with clean seed, flats, and growing media. Plant tolerant varieties. Avoid planting in fields with a history of strawberry or garlic anthracnose. Scout plants twice a week for symptoms; remove and destroy affected plants. Manage weeds, as several common species harbor celery anthracnose without clearly expressing symptoms. Remove or till under crop debris after harvest. A 3- to 4-year crop rotation with non-host plants should be followed. Avoid working the fields when the plants are wet, work in fields with a history of the disease last, and power wash equipment between fields. Research has shown that the strobilurin (Group 11) fungicides are most effective; however, be careful to rotate as resistance can develop quickly in this group.

FRAC Group 3:

• flutriafol (Rhyme): 5 to 7 fl oz/A; PHI 7d, REI 12h. Apply preventatively when conditions are favorable for disease development.

FRAC Group 7:

• pyraclostrobin + boscalid (Pristine): 10 to 15 oz/A; PHI 0d, REI 12h, Groups 11 & 7. Maximum of 2 applications per year.

FRAC Group 11:

• azoxystrobin (Quadris): 6 to 15.5 fl oz/A; PHI 0d, REI 4h. Do not apply more than once before alternating with a non-Group 11 fungicide.
• pyraclostrobin (Cabrio EG): 12 to 16 oz /A; PHI 0d, REI 12h. Do not apply more than once before alternating with a non-Group 11 fungicide.
• pyraclostrobin + boscalid (Pristine): 10 to 15 oz/A; PHI 0d, REI 12h, Groups 11 & 7. Maximum of 2 applications per year.
• pyraclostrobin + fluxapyroxad (Merivon Xemium): 4 to 11 fl oz/A; PHI 1d, REI 12h, Groups 11 & 7. Maximum of 3 applications per year.

Early Blight (Cercospora apii) and Late Blight (Septoria apicola)

The primary symptom of early blight (Cercospora apio) is the occurrence of small yellow spots that are visible from both sides of the leaf. These spots may develop into larger lesions that become papery and often tear. Gray, fuzzy fungal growth may be visible in well-developed lesions. Favorable temperatures for early blight range from 60ºF–86ºF. This pathogen can be seedborne and can survive on celery crop residue, and spores can spread via wind and water splashing.

Small, yellow, circular spots on leaves are also symptoms of late blight (Septoria apicola) in celery, which has similar symptoms to early blight in celery overall. One difference is that the small, round, and dark reproductive bodies of late blight, called pycnidia, can be seen in the center of lesions. This pathogen develops when temperatures are greater than 55ºF, and particularly in wet conditions when temperatures exceed 70ºF.

Use certified, disease-free seed or treat seed with hot water or fungicides. Practice careful sanitation in transplant greenhouses or rotate seedbeds. Irrigate early in the day to allow foliage to dry quickly. Use wider plant spacing and/or raised beds to improve air circulation. Plant resistant or tolerant varieties where available. Apply fungicides based upon a disease forecasting system.

FRAC Group 3:

• azoxystrobin + propiconazole (Quilt Xcel): 14 fl oz/A; PHI 14d, REI 12h, Groups 11 & 3. 
• propiconazole (Tilt): 4 fl oz/A; PHI 14d, REI 24h. Celery only.

FRAC Group 7:

• fluxapyroxad + pyraclostrobin (Merivon Xemium): 4 to 11.0 fl oz/A; PHI 1d, REI 12h, Groups 7 & 11.
• penthiopyrad (Fontelis): 14 to 30 oz/A; PHI 3d, REI 12h.
• pydiflumetofen + fludioxonil (Miravis Prime): 6.8 to 13.4 fl oz/A; PHI 0d, REI 12h, Groups 7 & 12. 
• pyraclostrobin + boscalid (Pristine): 10 to 15 oz/A; PHI 0d, REI 12h, Groups 7 & 11. Maximum 2 applications per year. 

FRAC Group 9: 

• cyprodinil + fludioxonil (Switch 62.5 WG): 11 to 14 fl oz/A; PHI 0d, REI 12h, Groups 9 & 12.

FRAC Group 11:

• azoxystrobin (Quadris F): 9 to 15.5 fl oz/A; PHI 0d, REI 4h. Do not apply more than once before alternating with a non-Group 11 fungicide.
• azoxystrobin + chlorothalonil (Quadris Opti): 2.4 to 3.7 pt/A; PHI 7d, REI 12h, Groups 11 & M05. See label for tank-mix precautions.
• azoxystrobin + propiconazole (Quilt Xcel): 14 fl oz/A; PHI 14d, REI 12h, Groups 11 & 3. 
• fluxapyroxad + pyraclostrobin (Merivon Xemium): 4 to 11 fl oz/A; PHI 1d, REI 12h, Groups 7 & 11.
• pyraclostrobin + boscalid (Pristine): 10 to 15 oz/A; PHI 0d, REI 12h, Groups 7 & 11. Maximum 2 applications per year. 
• trifloxystrobin (Flint): 2 to 3 oz/A; PHI 7d, REI 12h. Do not make more than once before alternating with a non-Group 11 fungicide.

FRAC Group 12:

• cyprodinil + fludioxonil (Switch 62.5 WG): 11 to 14 fl oz/A; PHI 0d, REI 12h, Groups 9 & 12.
• pydiflumetofen + fludioxonil (Miravis Prime): 6.8 to 13.4 fl oz/A; PHI 0d, REI 12h, Groups 7 & 12. 

FRAC Group BM02:

• Bacillus amyloliquefaciens F727 (Stargus^OG): 1 to 4 qt/A; PHI 0d, REI 4h.

FRAC Group M01:

• copper hydroxide (Kocide 3000): 0.75 to 1.5 lb/A; PHI 0d, REI 48h. Do not apply in a spray solution having a pH of less than 6.5 or tank mix with Aliette. An OMRI-listed formulation is available (Kocide 3000-O^OG).

FRAC Group M05:

• azoxystrobin + chlorothalonil (Quadris Opti): 2.4 to 3.7 pt/A; PHI 7d, REI 12h, Groups 11 & M05. See label for tank-mix precautions.
• chlorothalonil (Bravo Weather Stik): 2 to 3 pt/A; PHI 7d, REI 12h.

Fusarium Yellows (Fusarium oxysporum f. sp. apii)

Fusarium yellows causes yellowing of outer leaves, stunting, and eventually death. This pathogen spreads through plants’ vasculature. Infection may be spotty within fields, as symptoms are commensurate with the degree of infection. While this pathogen only infects celery, its spores can remain in soil almost indefinitely, surviving on celery crop residues, non-host crops, and many weed species. Once a field is infected, only resistant varieties can be grown. Rotating an infected field to onion or lettuce production for 2 years, before the pathogen becomes seriously problematic, is recommended to allow for spore decline. Good equipment and worker sanitation can reduce spread. Source resistant varieties and disease-free transplants. Avoid working fields when wet.

Basal Stalk Rot (Rhizoctonia solani)

Rhizoctonia in celery is sometimes called crater rot or simply stalk rot. Symptoms occur on petioles at soil level. Symptoms include reddish brown lesions on either side of the petiole that are sometimes sunken. This pathogen is soilborne and infects many plant species, including many vegetable crops. It is favored by warm, humid/wet conditions, and can survive in soil as sclerotia for a long time. A 2-year rotation is recommended. Avoid crops such as alfalfa and legume cover crops which can increase disease risk. Avoid cultivating late in the season. Maintain storage conditions at 50°F.

FRAC Group 11:

• azoxystrobin (Quadris): 0.4 to 0.8 fl oz/1,000 row feet; PHI 0d, REI 4h.
• azoxystrobin + chlorothalonil (Quadris Opti): 2.4 to 3.7 pt/A; PHI 7d, REI 12h, Groups 11 & M05. See label for tank-mix precautions.

FRAC Group 19:

• polyoxin D (OSO 5%SC^OG): 6.5 to 13 fl oz/A; PHI 0d, REI 4h. Celery only.

FRAC Group BM02:

• Bacillus amyloliquefaciens F727 (Stargus ^OG): 1 to 4 qt/A; PHI 0d, REI 4h.  

FRAC Group M05:

• chlorothalonil (Bravo Weather Stik): 2 to 3 pt/A; PHI 7d, REI 12h. Use sufficient water for adequate coverage.
• azoxystrobin + chlorothalonil (Quadris Opti): 2.4 to 3.7 pt/A; PHI 7d, REI 12h, Groups 11 & M05. See label for tank-mix precautions.

Pink Rot (Sclerotinia sclerotiorum)

Pink rot in celery is caused by the same pathogen that causes white mold in beans and peas. This pathogen can infect celery at any developmental stage but is most commonly seen near harvest. The most characteristic symptoms are lesions on the lower portion of petioles that are initially brown and then turn water-logged, slimy, and pink. Lesions can contain white mycelia and/or hardened black sclerotia. Severely infected plants may totally collapse. Infections can go unnoticed, especially on inner petioles. Symptoms can also appear during storage. Do not plant seed contaminated with sclerotia or plant into severely infested fields. Irrigate in the morning or with subsurface drip systems to promote drier soil. Rotate with non-hosts such as corn or small grains. Soil sterilization with chemicals, heat, or steam can reduce the number of viable sclerotia in the soil.

FRAC Group 7:

• boscalid (Endura): 7.8 to 9 oz/A; PHI 0d, REI 12h. 
• pyraclostrobin + boscalid (Pristine): 25 oz/A; PHI 0d, REI 12h, Groups 7 & 11. Maximum 2 applications per year. 

FRAC Group 9: 

• cyprodinil + fludioxonil (Switch 62.5 WG): 11 to 14 oz/A; PHI 0d, REI 12h, Groups 9 & 12. Make first application at thinning and once more 2 weeks later.

FRAC Group 11:

• pyraclostrobin + boscalid (Pristine): 25 oz/A; PHI 0d, REI 12h, Groups 7 & 11. Maximum 2 applications per year. 

FRAC Group 12:

• cyprodinil + fludioxonil (Switch 62.5 WG): 11 to 14 oz/A; PHI 0d, REI 12h, Groups 9 & 12. Make first application at thinning and once more 2 weeks later.

FRAC Group BM02:

• Bacillus amyloliquefaciens F727 (Stargus^OG): 1 to 4 qt/A; PHI 0d, REI 4h.
• Coniothyrium minitans strain CON/M/91-08 (Contans WG^OG): 1 to 4 lb/A; PHI 0d, REI 4h. Spray on soil surface and incorporate into top 2" soil. Apply in fall or 3-4 months prior to planting.
• Ulocladium oudemansii (U3 strain) (BotryStop^OG): 2 to 4 lb/A; REI 4h. Begin application when conditions are conducive to disease development.

FRAC Group M05: 

• chlorothalonil (Bravo Weather Stik): 3 pt/A; PHI 7d, REI 12h. Celery only. For disease suppression.